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G. REUTHE.

CUNTROLUNG WIRELESS TELEGRAPH THANSMITTFBS.

APPLCATION FILED MAY 25, I916.

1 ,308 ,5 30. Patented July 1, 1919.

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CONTROLLING WIRELESS-TELEGRAPH i 'IFRANSMITTERS.

Specification of Letters Patent.

Patented July 1, 1919.

Application filed May 25, 1916. Serial No. 99,793.

To all U/tO/ll it may concern:

Be it known that I, GUSTAV Ruurnn, a subject of the (iL'llI'ldll l hnperor, and residing at Sayville, Long island, New York, lime invented certain new and useful Im XU\'Ul!ltl]l.ii in Controlling \l'irclesS-Telegraph 'lriuisinitters. of which the following is a full specifi ation.

My invention is llllIhil'illQLl in the accompanying drawings and i s particular novel features are pointed out In the annexed claims.

The present invention rci'z'rs to means for stabilizing the energy output of a radio transmitter, utilizing frequency changers by which the fundamental frequency of the primary source of alternating current energy is multiplied to obtain the frequency required for radiation.

A transmitter of this character is for instance illustrated in the U. S. Patent No. 1,181,?(3, granted to Von Arco and Mcissher, and the present invention in particular constitutes an improvement in the operation of transmitters of this and similar characters.

The novelty of the means concerned in the present invention consists in suitably controlling the electrical cluu'actcristics of the several circuits of which such a transmitter arrangement is composed, and so far as these circuits constitute oscillating systems, that they are brought out of resonance to a certain degree with the fundamental frequency of the primary alternating current generator or an integral multiple thereof.

In the accompanying drawing a transmitter arrangement cont lining such fre quency changers is diagrammatically illustrated. V

In this diagram 1 is an alternating current generator of a comparatively high fun- (lamen i1 frequency (for instance 8,000 to 10,000 cycles per second) which might be suitably driven, for instance by direct coupling with an electromotor 2, as shown in the diagram. The frequency changers I, II, III are arranged in cascade so that for instance each of these elements may double the frequency supplied to it. These frequency changers are indicated diagrammatically merely by a square and may be of any suitable construction known in the art, for instance, in their general construction such as shown. in the aforesaid Areo-Meissner The circuit connections between the three frequency changers I,- II, III contain re: spectively the capacities 5 and 6 and the in- (luctances S and 9, all variable. The secondary of the high frequency changer III is connected with the antenna 10 containing the inductance 11. The antenna may be connected to the ground as shown.

It is, of course, obvious to any one skilled in the art that any suitable number of frequency changers may be arranged substantially as shown without departing from the spirit of my invention.

When transmitter arrangements of this character are operated, certain difficulties are encountered in maintaining a steady energy output. At certain frequencies and loads the condition of the whole system be comes unstable. In such condition a very slight variation of operating conditions, such as for instance the variation of the speed of the generator, or of the generator potential, or of the load, is sufficient to vary the current in the generator circuit in leaps so that it becomes very diflicult to maintaln a steady output, which renders the operation diflicult, and even sometimes impossible. Besides, the excess of potential which might result from such leaps is apt to endanger the entire installation. This danger is particularly great in case the=entire system is in resonance, that is to say. if the generator circuit is in resonance with the generator frequency and eaehintermediate circuit in resonance with that, multiple of the generator frequency which corresponds to the resulting multiple of the particular frequency changer sufpplying that intermediate circuit, and also i the antenna at the same time is in resonance with the frequency of the changer which supplies energy to it. In the endeavor to overcome difliculties of this character, it has been suggested before to increase thedamping of the interme iate circuits by interposing resistance. Vi hile this is indeed adapted to remedy these dilficulties, it is doneat the expense of the efiiciency, because such resistances consume energy.

By careful investigation I have found a means more efi'ective and economical in avoiding these dilticultics, which at the same time avoids the use of resistances and the accompanying needless 'aste of energy. This means provides that the generator circuit is deiimed with the generator frequency, and the intermediate circuits are detuned with the multiple oi the enerator fre uency supplied to them by t ieir par ticular frequency hanger. llspecially l avorable results are obtained when the tuning means (capacity and inductance) of the generator circuit and of the intermediate circuits are chosen larger than the values corresponding with the. exact resonance.

Moreover, very favorable results are ob tained in connection with the above mentioned expedient, when the antenna circuit. is not exactly in resonance with the multiple of the generator frequency supplied to it. In this case, however, the de'tuning must be such that the constants: (capacity and induction) which determine the resonance of the antenna circuit are made smaller than the values corresponding with. the resonant condition.

This whole expedient is particularly effective if at the same time the motor which operates the generator furnishing the fundamental frequency is provided with means for varying its energy output for a given speed or generally speaking with means for varying the load characteristic of the motor, so as to prevent the motor from running beyond the speed at which the entire system under given conditions is capable of taking up the maxin'inm energy. If the motor excoeds this critical speed, unstable conditions are established. In other words: these means should be such that they limit the output of the. motor at a given speed to a value which is below the maximum energy which the entire system can take up so that if by some reason the revolution number should increase, its output would tend to decrease, 2'. (a, so that the motor can never furnish quite the maximum energy which the electric system is capable of taking up.

In case the generator is driven electrically, as is assumed in the present case, where an eleetromotor 2 of any suitable con' struction may be coupled with the. generator, the means above referred 1110 For controlling the motor output is well 'known in the electrical art. For instance, in case of a direct current motor resistance may be placed in the armature circuit, and in case of a single or multiplephase alternating current motor resistance may be placed in the rotor circuits. However, any other suitable meai'is-irf motor control may also be used.

In the present case it may be assumed for example. that the generator 1 is coupled with connected to its armature for controlling the output which may be required to meet the given conditions of the transmitter.

In case the generator is driven by steam or water power, such means should be em ployed for th above purpose as is capable. of limiting the output of the driving motor to a speed to suit the given conditions of the system. For instance throttling valves or the like may he used for that purpose. An illiuiration of such means for control ling the driving motor has been omitted in the present application, inasmuch as they are well known.

The degree of de-tuning against l'e :omince. conditions should be determined so that the intended purpos; (1., the stabilizing of the whole system, is obtained. It is not advisable to carry the tie-tuning further, in order to avoid unnecessary decrease in elliciency. The most favorable degree ol do tuning! against resonan e condition may vary with the diti'erent conditions of opera iion, but anyone shilled in the art can easily find that point at which the system retains a suiiiciently high degree of etliciency at a sutiicient d gree. of stability to afford safe and steady, tqieration.

I claim:

1. A radio transmitting system comprising an alternating current generator for generating current at a fundamental frequency, an antenna for radiating energy at a desired integral multiple of the fundamental frequency. a number of frequencychangers and connecting circuits therefor interposed between the generator and the antenna acting to raise the generator trequencv to the desired multiple, the circuit containing; the generator being' dctuned against resonance with its own frequei'icy to the point of stability of the system.

2. A. radio transmitting system comprising an alternating current generator operating at a. i'uinlamental frequeni'ty, an antenna for radiating energy at a desired integral multiple of the fundamental frequency, and a plurality of freq!iency-changers with their connecting circuits interposed between the gei'ierator and the antenna for raising the generator frequency to the desired extent, each of the circuits being detuned against resonance with its own frequency to the point of stability oi the system.

3. A radio transmitting system comprising an alternating current generator for gonorating current at fundamental frequency, an antenna for radiating energy at an integral multiple of the fundamental frequency, and a. number of frequency-changers and their connecting circuits between the generator and the antenna for raising the generator Frequency to the integral multiple desired for the antenna; the circuits connecting the generator and the frequencychangers and antenna heing detuned. the generator circuit against resonance with the fundamental frequency, and each l'reipienrywhanger circuit against resonance to its respective integral multiple of the fundamental frequency.

-l. A radio transmitting system comprising a generator of aiternating current at fundamental frequency, an antenna for radiating energy at a desired integral multiple of the fumlamental frequency, and a number of frequency-change s and connecting circuits therefor between the generator and the an tenna. the circuits including capacity and inductance: the capacity and inductance in the generator circuit being larger than is required to tune the circuit toresonancc with the fundamental frequency, and the capacity and inductance of each of the frequency' changer circuits being larger than is required to tune the circuits to resonance with their respective frequencies.

7. A radio transmitting system comprising a generator of electric currents at fundamental trequeney, an antenna for radiating energy at a desired multiple of the fundamental frequency, and a number of tre quency-changcrs and connecting circuits be tween the generator and the antenna, the circuits containing capacity and inductance; the capacity and inductance ot' the antenna circuit being smaller than is required to tune the antenna circuit to resonance with its own frequency.

(1. A radio transmitting system comprising a generator of electric currents at tunclamental frequency, an antenna radiating en ergy at a higher frequency, and a number at frequeneychangers and connecting circuits between the generator and the antenna, the several circuits containing inductance and capacity; the inductance and capacity of the generator and frequents/changer circuits being larger, and those of the antenna circuit hciug smaller. than is required to tune the several circuits to resonance with their respective frei'piencies.

T A radio transmitting systemeomprising a generator of electric currents at fundamental frequency, an antenna 'adiating energy at a higher frequency, and a number of t'reqi|encychangers and connecting eirenitu between the generator and the antenna, the several circuits containing inductance and capacit the induct anee and capacity of the generator and frei |leney changer circuits being larger, and those of the antenna circuit heinc smaller, than is required to tune the several circuits to resonance with their respective t'reqmuicies; in combination with driving means for the generator, provided with means for varying its energy output, the said output being so controlled as to prevent the drivingmeans reaching a speed at which the system ahsorhs maximum energy.

3. A radio transmitting system comprising a generator of electric currents at fundamental trequeu y, an antenna radiating energy at a higher frequency, and one or more 'i ltqlllfllt'yji'll:lllgtl'fi and connecting circuits between the generator and the antenna, the several circuits containing inductance and capacity; the inductance and capacity of the generator and frei' ueneva-hanger circuits being larger. and those of the antenna circuit being: smaller, than is required to tune the several circuits to resonance with their respective frequencies: in combination with an electric motor for the generator, provided with means for varying its energy output, the said output being so controlled as to prevent the motor reaching a speed at which the s stern ahserhs maximum energy.

GUSTAV REU THE. 

